Safety guard for shaping tool

ABSTRACT

A guard for a table-mounted hand shaping tool includes a shield comprising a U-shaped upstanding panel mounted on a pair of rearwardly extending support members. At rest on the table the Ushaped panel surrounds the forward and side portions of a cutterhead, which extends upwardly above the surface of the table, while leaving the rearward portion open. The support members are pivotally mounted on upright brackets fastened to the table for fore and aft pivotal movement about an axis generally parallel to the plane of the table. A pair of transverse members are mounted on the support members. A pneumatic cylinder is fixedly mounted to the pair of transverse members. The pneumatic cylinder has a reciprocable piston with a rod attached thereto and extending downwardly from the cylinder. The free end of the rod carries a captive ball socket which bears against the table surface. Upon remote actuation of the pneumatic cylinder, the piston translates in the cylinder and causes the cylinder to rise and consequently causes the entire guard assembly to pivot upwardly and rearwardly about its pivotal mounting axis, thereby allowing a workpiece to engage the cutterhead. If desired, the guard can be pivoted to a remote rearward position for ready access to the cutterhead for changing blades and maintenance.

United States Patent [191 York [ 51 Jan. 14,1975

[ SAFETY GUARD FOR SHAPING TOOL [76] Inventor: Daniel R.York,9l5l E.52nd,

Tacoma, Wash. 98424 [22] Filed: Sept. 12, 1973 [21] Appl. No.: 396,602

Primary Examiner-Andrew R. Juhasz Assistant Examiner-W. D. BrayAttorney, Agent, or Firm-Christensen, OConnor, Garrison & Havelka [57]ABSTRACT A guard for a table-mounted hand shaping tool includes a shieldcomprising a U-shaped upstanding panel mounted on a pair of rearwardlyextending support members. At rest on the table the U-shaped panelsurrounds the forward and side portions of a cutterhead, which extendsupwardly above the surface of the table, while leaving the rearwardportion open. The support members are pivotally mounted on uprightbrackets fastened to the table for fore and aft pivotal movement aboutan axis generally parallel to the plane of the table. A pair oftransverse members are mounted on the support members. A pneumaticcylinder is fixedly mounted to the pair of transverse members. Thepneumatic cylinder has a reciprocable piston with a rod attached theretoand extending downwardly from the cylinder. The free end of the rodcarries a captive ball socket which bears against the table surface.Upon remote actuation of the pneumatic cylinder, the piston translatesin the cylinder and causes the cylinder to rise and consequently causesthe entire guard assembly to pivot upwardly and rearwardly about itspivotal mounting axis, thereby allowing a workpiece to engage thecutterhead. If desired, the guard can be pivoted to a remote rearwardposition for ready access to the cutterhead for changing blades andmaintenance.

10 Claims, 3 Drawing Figures PATENTED JAN 1 41875 SHEET 10F 2 wmllmipPATENTEDJAN 1 4|975 sum 2 or 2 SAFETY GUARD FOR SHAPING TOOL BACKGROUNDOF THE INVENTION The present invention relates to a safety device for arotating cutterhead mounted on a table and, more particularly, to asafety shield for a table mounted hand shaper.

Machines known as hand shapers are generally used in the woodworking artto shape the edges'of planar sections of wooden workpieces. Such edgesare shaped by free hand manipulation of the workpiece or by following apreshaped form. Generally, hand shapers are mounted on a table having aplanar top surface and have a cutterhead shaft extending upwardly abovethe surface of the table at generally right angles thereto. A cutterknife is attached to the portion of the shaft extending above thesurface of the table. Generally these knives are very securely fastenedto the shaft by means of a threaded retaining nut.

Upon failure of the knife, the shaft or some other catastrophic failureof the cutterhead, fragments occasionally separatefrom the cutterheadand are expelled in a direction tangential to the rotation of the shaft.Since these shaftsgenerally rotate atvery high speeds, on the order ofsix :to ten thousand rpm, the knives upon acci dental separation fromthe shaft travel at great velocities presentinga great potentialdangerto the operators andother individualsin the vicinity of the handshapers. Based on .past experience, it has been learned that knivesgenerally will separate from the shaft during start-up,whenthe shaft isaccelerating fromthe rest to operating speed,andduring shutdown, whenthe shaft is slowing from operating speed to rest. The knives mayseparate fromthe shaftwhen the machine is running at operating speed,but when no workpiece is present in front of the knife. When the knife.is operating on a workpiece the workpiece itself provides a sufficientguard to prevent injury from accidental separation of knives from theshaft.

In order to provide a machinewhich is safe for an operator to manipulateduring periods of high stress on the cutterhead,it is desirable toemploy acutterguard which will prevent knives from injuringpersons inthe vicinity of the machine should they accidentally separate fromtheshaftSeveral prior art means for solving this safety problem "have beensuggested; however, most of these require large and cumbersome mechanismfor operation and are expensive and difficult to operate. Furthermore,it is desirable to obtain some measure of protection during actualmanipulation of a workpiece against the cutterhead. Priorart guards havenot provided any substantial amount ofprotection during this period.

A broadobject of .thepresent invention is to provide a safety devicefor. arotatingcutterhead mounted ona table which fulfills theforegoingdesirable attributes. Further objectsofthepresent invention aretoprovide a guard whichraises above the-cutterhead to aheightsufficientto provide agood view of thecutterhead and workpiece beingmanipulated while simultaneously providing a-measure of safety fromblades which may accidentally separatefrom the shaft; to provide aguardwhich is capableof pivoting rearwardly out of the vicinity of thecutterheadin orderto allow ready access to the head for maintenance andreplacement; to provide a guard whichin its operativejposition duringshaping rests only a small distance above the workpiece, which distancecan be adjusted to allow for different workpiece thicknesses, therebyproviding maximum protection during operation of the machine; to providea cutterhead guard which can be easily installed on existing shapers; toprovide a cutterhead guard which can be remotely operated; to provide acutterhead guard which is relatively inexpensive to manufacture andwhich requires little maintenance; and to provide a power means foroperating the guard or safety device from an energy source readilyavailable in most woodworking shops.

SUMMARY OF THE INVENTION The foregoing objects and other objects whichwill become apparent upon reading the following specification arefulfilled by a novel safety device for a rotating cutterhead mounted ona table. The device includes a movable guard means having a forward wallportion and spaced sidewall portions extending rearwardly therefrom.Mounting means is provided to locate the guard means in a first positionin which the wall portions are located adjacent to the table and extendupwardly therefrom to define a region surrounding the front and sides ofthe cutterhead. The mounting means is capable of pivoting the guardmeans upwardly about an axis parallel to the table and transverse to therearwardly extending side wall portions to a second position in which aworkpiece can be slid under the guard means for access to thecutterhead. In the second position the guard means stillprovidesprotection by surrounding the portion of the cutterheadextendingabove BRIEFDESCRIPTION OF THE DRAWINGS A betterunderstanding ofthe present invention can be derived by reading the ensuingspecification in conjunction with the accompanyingdrawings wherein:

FIG. 1 is an isometric view illustrating the guard assembly of thepresent invention from the rear aspositionedover the .work table of awood shaping tool when no workpiece is present;

FIG. 2 is a plan view of the assembly ofFIG. l;an

FIG. 3 is a side elevation view of the assembly of FIG. 1 showing theguardin a second position when artworkpiece is beingshaped and inathirdposition (in ghost outline) .providing easy access to thecutterhead for maintenance.

DESCRIPTION OF PREFERRED EMBODIMENT FIGS. 1, Zand 3 portray a cutterheadl0 mounted on a table 12 formilng part of a powered hand shaping tool ofthe type used to shape theedges and sides of wooden beams boards, panelsand the like. The front of the shaping tool is at the left side asviewed in all FIG- URES..In operation a workpieceis moved into thecutterhead 10 from the front and is moved generally from right to leftby an operator to shape the edge of the workpiece. The guard assembly,generally designated 14, is installed onthe table 12. It has fourfunctional parts which include mounting brackets 16, frame 18, shield 20and a pneumatic cylinder operating mechanism'22.

The frame 18 is the primary structural member of the guard assembly 14,providing support for the shield 20 and fixing its positions relative tothe cutterhead 10. The frame has two tubular arms or rods 32'whichextend rearwardly from the shield 20 and which are welded or otherwisesuitably affixed to the sidewalls thereof. The arms 32 are transverselyinterconnected by parallel bars 34. Mutually aligned stub shafts 28 areaffixed in transverse relationnship to the rearward ends of the tubulararms 32. Mounting brackets 16 are bolted to the rear top surface oftable 12. In this location the brackets 16 do not interfere with theworkpiece when it is engaged with the cutterhead 10. The brackets 16have axially aligned mounting holes 26 which receive the stub shafts 28,thereby establishing a pivotal axis 30 about which the shield and framecan pivot while being lowered and raised.

The shield 20 has a generally U-shaped cross-section when lookingdownwardly from the top. It has a for ward wall and spaced sidewallsextending in a smooth curve rearwardly from the forward wall. The wallsexend generally perpendicularly upwardly from the surface of the table12 to form a region sufficiently large to enclose the cutterhead 10 onthree sides. For most applications the rearward, portion of the shieldis open since the rear side of a shaper of this type is usually abuttedagainst a wall or-has an integral rear shield. The shield 20 isfabricated from sheet metal or other suitable impact resistant material.If desired the shield 20 can be constructed from a transparent highimpact plastic to allow the operator to visually monitor the status of aworkpiece at the cutterhead 10. The stub shafts 28 are secured to thebrackets 16 with cotter pins 36.

By appropriately choosing the length of the arms 32 and the location ofthe brackets 16, the shield 20 can be located so that in a loweredposition, as shown in FIG. 1, the bottom of the shield 20 is locatedbelow the plane of rotation of the knives on the cuutterhead 10. Aspacer 38 is attached to the bottom of the sidewalls of the shield 20and rests on the top surface of table 12 of the shaping tool. The spacersupports the shield 20 in its lowered position. The shield is placed inthe lowered position when a workpiece is not engaged with the cutterhead10, allowing the guard assembly 14 to provide maximum protection fromblade separataion as well as preventing inadvertent contact with therotating cutterhead itself.

Support brackets 40 mounted on the transverse parallel bars 34 provide abase through which a pneumatic actuating cylinder 42 is attached to theframe 18. When energized, the actuator 42 functions to lift the guardassembly 14 from the surface of the operating table surface 12sufficiently far to allow a workpiece 44 (FIG. 3) to be inserted underthe bottom of shield 20 and to engage the cutterhead 10. A push-typepneumatic actuator is preferably employed. A rod or plunger 46,connected to a piston in the cylinder 42, extends from the cylindertoward the table 12.. The plunger 46 terminates at its lower end in acaptive ball and socket fixture 48 which reduces the frictionbetween theplunger 46 and the table surface 12 to a negligible value as theassembly is cycled about its pivotal axis. When pneumatic pressure isapplied to the cylinder, it rises upwadly carrying the frame 18 andshield 20 along. the pneumatic actuator cylinder 42 can be actuated by afoot-operated valve or the like (not shown) via an air hose 58. Othersuitable actuators can be used as desired.

A pair of studs 52 is affixed to a plate 50 associated with the ballfixture 48. The studs 52 are located parallel to the plunger'46 andslidably engage holes 54 in support brackets 40. The studs areeffectively a part of the plunger 46 and extend and retract through theholes 54 in the brackets 40 conjunctively with the plunger 46. Thetravel of the studs 52 through the bracket holes 54 is adjustablylimited by the knurled nuts 56, which are threaded on the ends of thestuds 52. Turning the nuts toward the free ends of the studs-allows'theplunger 46 to extend further toward the table 12, thereby allowing theguard to be raised higher. Turning the nuts 56 in the opposite directionrestricts the translational distance of the plunger 46 to its shorterstroke, thereby reducing the lifting distance.

The guard assembly 14 as illustrated in FIG. 1 shows the actuator 42 ina deactivated position with the spacers 38 resting on the table 12 toprovide maximum protection for the operator. FIG. 3 illustrates theguard assembly 14 as it appears with foot pedal (not shown) depressedthereby energizing the penumatic actuator 42. The plunger 46 isextended, elevating the guard assembly l4 rearwardly and upwardly aboutpivotal axis 30. When the shield 20 is elevated, a workpiece 44 can beapplied to thecutte'rhead 10. Raising the guard'assembly 14 in thismanner affords the operator physical and visual access to the cutterhead10 while maintaining protection during the shaping operation.

As shown in ghost outline in FIG. 3, the guard assembly 14 can bemanually pivoted beyond its raised operational position in the directionindicated by arrow 60 to a stowed position to allow accessto thecutterhead for maintenance. In the stowed position a rod 62 affixed tothe rear portion of arm 32 and extending perpendicularly therefrom bearsagainst the table 12 to limit the rearward travel, of the guard assembly14.

The present invention has been described in relation to a preferredembodiment. One of ordinary skill in the art will be able to effectvarious alterations to substitutions of equivalents in, and otherchanges to that embodiment without departing from the orginal conceptdisclosed herein. It is therefore intended that the present invention belimited only by the definition contained in the appended claims.

What is claimed is:

l. A safety device for a rotating cutterhead mounted on a tablecomprising:

guard means having a forward upright wall portion and spaced uprightsidewall portions affixed to and extending rearwardly from said forwardwall portion, said, guard means defining a region enclosed on at leastthree sides, said region being sufficiently large to enclose acutterhead protruding from said.

table, said guard. means including a support member affixed thereto andextending rearwardly there-,

from, v mounting means for attaching said support member to said tablefor selective upward and rearward piv- ,1 otal movementabout an axisgenerally parallel to said table, said axis being located rearwardly ofsaid cutterhead, said mounting means capable of supporting said guardmeans for movement from a first position surrounding said cutterhead toa second position located above said first position wherein a workpiececan be moved across said table and under said forward wall and sidewallportions and from said second position to a third stowed positionwherein at least a substantial portion of said guard means ispositioned, relative to said first position of said guard means,rearwardly of said axis.

2. The safety device of claim 1 wherein said forward wall portion andsaid sidewall portions comprise a panel of generally U-shapedcross-section extending upwardly from said table, said sidewall portionsterminating in rearward, upright edges, said panel being open betweenthe rearward edges of said sidewall portions.

3. The safety device of claim 2 wherein said support member comprises anarm attached to and extending rearwardly from each rearward edge of thesidewall portions of said U-shaped panel, and wherein said mountingmeans comprises bracket means for attachement to said table, saidbracket means capable of extending upwardly from said table, andmutually aligned stub shafts extending generally parallel to said tableand transversely from each of said arms, said stub shafts cooperatingwith said bracket means to mount said arms for pivotal movement aboutsaid axis.

A safety device for a rotating cutterhead mounted on a table comprising:

guard means having a forward upright wall portion and spaced uprightsidewall portions affixed to and extending rearwardly from said forwardwall portion, said guard means defining a region enclosed on at leastthree sides, said region being suffiently large to enclose a cutterheadprotruding from said table, said guard means including a support memberaffixed thereto and extendingrearwardly therefrom,

mounting means for attaching said support member to said table forselective upward and rearward pivotal movement about an axis generallyparallel to said table, said mounting means capable of supporting saidguard means for movement from a first position surrounding saidcutterhead to at least a second position located above said firstposition wherein a workpiece can be moved across said table and undersaid forward wall andsidewall portions, and,

a fluid operated cylinder means mounted on said support member at aposition forwardly of said axis, said cylinder means including a pistonhaving a piston rod connected thereto and extending downwardly towardsaid table and having means on the free end thereof for bearing againstsaid table, said cylinder thereby mounted for reciprocal movement towardand away from said table upon extension of said piston, thereby causingsaid guard means to pivot about said axis.

5. The safety device of claim 4 wherein said sidewall portions terminatein rearward upright edges, said support member comprising an armattached to and extending rearwardly from each rearward edge of thesidewall portions and a transverse member affixed to and extendingbetween said arms, said cylinder being affixed to said transversemember.

6. The safety device of claim 5 wherein said cylinder means includesmeans for adjusting the reciprocal travel distance of said piston rod.

7. The safety device of claim 4 wherein said means on the end of saidpiston rod comprises a socket connected to said piston rod and a ballmounted for rota tion in said socket for bearing against said table.

8. The safety device of claim 4 further comprising:

means operable from a location remote from said guard means and mountedthereon for actuating said cylinder means to move said guard meansbetween said first and second positions.

9. The safety device of claim 1 further comprising:

an arm means rigidly connected to and extending upwardly from saidsupport member, said arm acting as a stop for pivotal movement of saidguard means when said guard means is moved to said third stowedposition.

10. The safety device of claim 1 further comprising:

stop means attached to the bottom portion of said guard means forlimiting the pivotal travel of said guard means downwardly toward saidtable about said axis thereby fixing the distance at which said guardmeans rests above said table in said first position.

1. A safety device for a rotating cutterhead mounted on a tablecomprising: guard means having a forward upright wall portion and spacedupright sidewall portions affixed to and extending rearwardly from saidforward wall portion, said guard means defining a region enclosed on atleast three sides, said region being sufficiently large to enclose acutterhead protruding from said table, said guard means including asupport member affixed thereto and extending rearwardly therefrom,mounting means for attaching said support member to said table forselective upward and rearward pivotal movement about an axis generallyparallel to said table, said axis being located rearwardly of saidcutterhead, said mounting means capable of supporting said guard meansfor movement from a first position surrounding said cutterhead to asecond position located above said first position wherein a workpiececan be moved across said table and under said forward wall and sidewallportions and from said second position to a third stowed positionwherein at least a substantial portion of said guard means ispositioned, relative to said first position of said guard means,rearwardly of said axis.
 2. The safety device of claim 1 wherein saidforward wall portion and said sidewall portions comprise a panel ofgeNerally U-shaped cross-section extending upwardly from said table,said sidewall portions terminating in rearward, upright edges, saidpanel being open between the rearward edges of said sidewall portions.3. The safety device of claim 2 wherein said support member comprises anarm attached to and extending rearwardly from each rearward edge of thesidewall portions of said U-shaped panel, and wherein said mountingmeans comprises bracket means for attachement to said table, saidbracket means capable of extending upwardly from said table, andmutually aligned stub shafts extending generally parallel to said tableand transversely from each of said arms, said stub shafts cooperatingwith said bracket means to mount said arms for pivotal movement aboutsaid axis.
 4. A safety device for a rotating cutterhead mounted on atable comprising: guard means having a forward upright wall portion andspaced upright sidewall portions affixed to and extending rearwardlyfrom said forward wall portion, said guard means defining a regionenclosed on at least three sides, said region being suffiently large toenclose a cutterhead protruding from said table, said guard meansincluding a support member affixed thereto and extending rearwardlytherefrom, mounting means for attaching said support member to saidtable for selective upward and rearward pivotal movement about an axisgenerally parallel to said table, said mounting means capable ofsupporting said guard means for movement from a first positionsurrounding said cutterhead to at least a second position located abovesaid first position wherein a workpiece can be moved across said tableand under said forward wall and sidewall portions, and, a fluid operatedcylinder means mounted on said support member at a position forwardly ofsaid axis, said cylinder means including a piston having a piston rodconnected thereto and extending downwardly toward said table and havingmeans on the free end thereof for bearing against said table, saidcylinder thereby mounted for reciprocal movement toward and away fromsaid table upon extension of said piston, thereby causing said guardmeans to pivot about said axis.
 5. The safety device of claim 4 whereinsaid sidewall portions terminate in rearward upright edges, said supportmember comprising an arm attached to and extending rearwardly from eachrearward edge of the sidewall portions and a transverse member affixedto and extending between said arms, said cylinder being affixed to saidtransverse member.
 6. The safety device of claim 5 wherein said cylindermeans includes means for adjusting the reciprocal travel distance ofsaid piston rod.
 7. The safety device of claim 4 wherein said means onthe end of said piston rod comprises a socket connected to said pistonrod and a ball mounted for rotation in said socket for bearing againstsaid table.
 8. The safety device of claim 4 further comprising: meansoperable from a location remote from said guard means and mountedthereon for actuating said cylinder means to move said guard meansbetween said first and second positions.
 9. The safety device of claim 1further comprising: an arm means rigidly connected to and extendingupwardly from said support member, said arm acting as a stop for pivotalmovement of said guard means when said guard means is moved to saidthird stowed position.
 10. The safety device of claim 1 furthercomprising: stop means attached to the bottom portion of said guardmeans for limiting the pivotal travel of said guard means downwardlytoward said table about said axis thereby fixing the distance at whichsaid guard means rests above said table in said first position.